Because a Big Brother Database of my contacts isn’t complete if I
don’t keep track of what e-mail I sent them and when I sent it, this
bit of Emacs Lisp code adds Gnus subjects to the BBDB records of the
people to whom I sent e-mail.

It should be really easy to set up Gnus to expand some kind of
!followup macro into a TODO item in my planner and an “I hope to hear
from you by ….”. Ridiculously easy with Emacs Lisp and an insanely
customizable editor, but I might not have enough battery life. I’ve
got 28 minutes, and then I’m off PC for a while.